THE SUGAR-CANE LEAFHOPPER. OM | 
Cane raised specially for seed and not stripped until wanted for planting is more 
likely to be free from insect punctures, and will therefore be less likely to develop 
rind disease after planting. 
Mr. L. Lewton-Brain in a report on the rind disease thus describes 
the relation between the leafhopper and the disease: ¢ 
Under field conditions, of course, the spores gain access to the interior of the plant 
through natural wounds. Perhaps the most abundant wounds offered for this pur- 
pose are leafhopper punctures; even more favorable for the fungus are the tunnels of 
borers, leading as they do right into the heart of the sugar-containing tissue; other 
wounds may be made in stripping; in fact, it is a difficult matter to find a ie of 
cane without a wound of some sort. The spores are produced in immense numbers 
on every stick of rotten cane. They are doubtless distributed partly by the wind, 
though the mucilaginous substance by which they are joined does not favor this; 
insects are certainly also important distributers of the spores, leafhoppers will get 
infected and deposit the spores in their punctures, ants will carry them into borer 
and other wounds in their search for food, flies may also serve the fungus in the same 
way. 
The control of the rind disease of cane on the plantation will be 
another factor in reducing leafhopper injury. Since the leafhopper 
can not be exterminated and the punctures from this insect will 
always occur on a plantation to a greater or less degree, it becomes 
particularly essential for the planter to eradicate the RCE. 
On the control of the rind disease, Doctor Cobb has the following 
on pages 109 and 110 of his report'referred to above: 
The number of spores of this disease that exist on every plantation is past calcula- 
tion, and almost inconceivable. This abundance of the spores of the disease tends 
of course to increase the losses. If there were no spores there could be no rind dis- 
ease. Anything that can be done to reduce the number of spores will tend to reduce 
the amount of the disease. Something can certainly be done in this direction. Stalks 
dead of the disease can be destroyed, and there can be no doubt that in some cases 
expenditure in this direction will be well repaid. There can be no doubt that the 
collecting and complete destruction of the stalks on the field would be a paying 
operation. How to destroy them is the question. The ordinary burning off destroys 
only a part of these rind disease stalks, leaving the rest untouched or only partially 
roasted, to go on producing their millions upon millions of spores. 
It is the custom on all the Hawaiian plantations to leave on the ground after harvest 
the sticks of cane that have been attacked by borers or are worthless for other reasons. 
The reason for this is easy to understand. Such material is unsuitable to the highest 
efficiency of the mill as an extractor of cane juice. It is also of such a nature that 
it may interfere with the clarification, evaporation, or crystallization. 
Notwithstanding this I think it ould be advisable to consider whether this material, 
which is really a menace to the health of future crops, cannot in some way be run 
through the mill and burned. This is a practice adopted in some other parts of the 
world. On Saturday afternoons a special run of the mill is devoted to the milling of 
such refuse as I have mentioned, the “bagasse” being burned. The juice is alone 
to run to waste, being first ated by heat. 
In Hawaii it is usual to attempt to burn this diseased material, but from careful 
observation I am certain that this attempt often ends in failure, that is to say the 
disease that exists in the waste-cane is only partially destroyed. 
¢ LEwTon-Brain, L.—Rind disease of the sugar cane. <(Hawaiian Sugar Planters” 
Exp.-Sta,-Div.Path., Bul. 7, p. 21, 1907. 
